To explore the neural coding mechanisms by which the hippocampal region mediates declarative memory, single neurons will be recorded in behaving rats as they sample a series of stimulus items, then judge either the sequential order or the familiarity of the items on the sample list. I will test the hypothesis that the hippocampus encodes information about the sequential positions of the items whereas the adjacent perirhinal cortex encodes item familiarity (i.e., whether or not the item was on the list). The proposed experiments are guided by recent findings with humans that have been taken as evidence for a selective role for the hippocampus in episodic memory and for the surrounding cortex in semantic memory. Also, recent findings in animals suggest sequence memory is an important feature of hippocampal involvement in episodic memory. A basic understanding of the mechanisms by which long-term memories are encoded by neurons in the hippocampus and surrounding cortex is fundamental to understanding declarative memory and to addressing disorders of memory.